Exhaust device for engines



H. T. H ERR EXHAUST DEVICE ENGINES Filed Dec. 51, 1920 I June 21, 1927. 6

w-brtrigm- Patented June 21,1921. T 1

the a paratus UNITED STATES 1,632,896 PATENT OFFICE.

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My invention relates to internal combustionengines and has particular reference to scavenging mechanisms for internal combustion engines of the four-cycle type.

An object of my invention 1s to provide an improved and eflicient scavenging device for internal combustion engines the fourcy'cle t pe in which the heat of the engine 'is utilihed to effect the scavenging operation;

A further-object is to increase the eflicienc of an internal combustion engine of,

the our-c cle. b rovidi a ressure below atmds pfieriz vyithin t l l cyli hder duringthe exhaust stroke of the engine, thus converting the exhaust stroke into a secondary work stroke.

These and other ob'ects, which will be made apparent throng out the description;

of my invention are attained by means of described herein and illustrate 1n the accompanying drawings in whichy 7 Figure 1 is a longitudinal sectional view of an internal'combustion engine equipped with a scavengin mechanism.

Figure 2 is a ongitudinal sectional view" of a modification of a construction illustrated in Figure 1;

Figure?) isa pressure-volume diagram of an internal combustion engine operating with my improved scavenging device.

It has heretofore been pro to increase the efiiciency' of an inte combustion engine by a thorough scaveng' of the engine cylinders, and in engines of t e Diesel type, it is highly important that the burned gjgfis be as completely removed as ible. 's has been commonly accomplis ed in internal combustion engines of the four-cycle type by 1permitting the iston on the exhaust .stro e to force the urned gases from the cylinder. In some cases it has been pro posed to scavenge the clearance space by supplying air under pressure to the engine cylinder, the best results being obtained by air enterin at from five to ten Pounds gage pressureJ his specific type 0 scavenguin necessitates the use of air compressors w c decrease the overall efiiciency of the engine and are a source of considerable trouble in their mechanical upkeep. My invention accomplishes the scavenging of an engine 0 linder by reducing the pressure within e cylinder to from six to ten pounds below atmospheric prewure. This method not only thoroughly scavenges the c linder and the clearance space but accom es-a net am in work during the e aust stroke. e latter result is due to the fact that the higher atmospheric pressure acts u n the outer surface of the piston while t e preswe 'r'r. or men, mnsnvmra, assienoa r0 wns'rmenouslnucsurewithin the cylinder acting uponthe inn'er surfaceof-the piston is at a considerably lower pressure.

- The energy necessary to produce this con-' dition of low pressure wit in the linder during the exhaust stroke is by the heat in the engine walls, which is .no mally dissipated in the coolin system. The cooling water is circulated t ough the engme jacket and the steam thus generated is utilized to opferate an ejector which maintains a cham r at a low, sub-atmospheric pressure. The exhaust manifold is in communication with this chamber so that a low pressure is maintained within the exhaust manifold. The a paratus comprising a low-pressure. cham r and an ejector coo crates with the engine iston only on t e exhaust stroke; that is urin three strokes of the engine cycle,-the suction stroke the compression stroke, and the working stroke-, the exhaust valve is closed and the ejector operates during these strokes only to create and maintain a vacuous condition within the low-pressure chamber.

It willbe seen from the above description that an efiicient scavenging device is rovided which not only does not im ose a oad upon the engine, but actually a ds to the mean effective power of the engine.

Referrin re 1 an internalcombustion engine 10 having a cylinder 11 surrounded by a A'acket 12 to provide a water chamber 13 piston 14 is arranged to reciprocate within the cylinder 11. Power is transrespectively, which may be operativ'elyconto the drawingyl have illustrated 1n igu mder 11. From the chamber 25 the exhaust gases are led by means of a conduit 26 to an ejector 27.

Conduits 30 and 31 communicate with the upper portions of the water chambers 13 and 16.and lead through a conduit 33 into a steam-separating chamber 34. A conduit 35 leads-from the lower portion of the steamseparating chamber 34 to the lower portion of the chamber 13. A pump 36 may be interposed within conduit for producin a continuous circulation of water throug the en ejacket and steam-cooling chamber l t is obvious, however, that a circulation of water would be maintained without the use of the pump and I may provide a by-pass conduit equipped with a check valve so disposed that water may freely pass from the conduit 35 to the water jacket 13 without led rom t e steam-coolin chamber 34 to a steam chamber 40 of t e ejector 27 by means of a conduit 39. Steam is discharged from chamber 40 through nozzles 41 into a diver in portion 42 of the ejector. The mixed ui s are then discharged through a diffuser 43 to the atmosphere.

Having described the arrangement of a device embodying my invention, the operation thereof is as follows: When the engine is placed in operation, the heat transmitted through the cylinder 11 raises the temperatureof the water in the jacket 13 and thus produces a circulation of water through the jacket 13, conduit 33, chamber 34 back to the jacket 13. When the water has been sufiiciently heated, the steam which forms in the jacket 13 is separated from the water in the chamber 34 and thence delivered to the ejector 27. The con- 4 tinuous discharge of steam through the ejector 27 serves to maintain a relatively low, sub-atmospheric pressure within conduit 26 and the chamber 25 so that upon opening of the exhaust valve 18, the pressure within the cylinder 11 immediately to restore a higheyacuous falls below atmospheric pressure. The higher atmospheric pressure acting upon the under side of the piston 14 produces a secondary inward wprkstroke. The gases thus exhausted into the chamber 25 are removed by, the action of the ejector 27 and after valve 18 is closed, the injector serves condition within the chamber 25.

In Figure 2, I show a slightly modified form of the apparatus illustrated in Figure .1. The. construction of the engine,

assin through the pump. Steam is jackets, water circulating system, and the arrangement of the valves are identical with that described above in relation to Fig. 1,

and a description thereof need not be here repeated. In this modification, the exhaust ases escaping through the valve 18 are deivered to an ejector through a conduit 51. Communicating with the conduit 51 is a chamber or reservoir 52 of considerably greater capacity than the cylinder 11. Steam is delivered to the ejector 50'through the conduit 39 and the nozzle 53, which is I arranged interiorly of and concentrically with the diverging portion 54 of the ejector 50. The steam and gases are finally discharged to the atmosphere through the diffuser 55.

The operation .of the apparatus illustrated in Figure 2 differs from that described above in relation to Figure 1 only in the arrangement of the low-pressure chamber or reservoir. In the latter construction, the ejector 5 maintains the chamber 52 in a high-vacuous condition. Upon'the, opening of the exhaust valve 18, part of the exhaust gases are discharged directly to the ejector 50 and the remainder of the gases are drawn into the chamber 52, the result being .an almost immediate fall in pressure within the cylinder 11 to a sub-atmospheric pressure, which is maintained during the entire exhaust stroke by the cooperative action of the ejector 5,0 and the low-pressure chamber y The pressure-volume diagram illustrated in Figure 3 shows the Work accomplished both during the combustion or primary work stroke and during the exhaust or secondary work stroke. In this diagram, the line AB--C represents the compression stroke, the line CD-A, the combustion stroke, the line A--EF, the exhaust stroke and the line F"G.A, the suction stroke. It will be apparent from an inspection of this diagram that the .added power delivered by myimproved engine is represented by the area A-E-FG, and that since this is accomplished without in anyway decreasing the power of the primary work stroke, represented by the area AB--CD, the mean effective power of the engine has been-increased by an amount equiva area AE-FG It is apparent from the above descriptiom of the structure and o ration of my im proved scavenging mec anism that an increased mean'efiective power is obtained in a four-cycle internal combustion engine, constructed according to m invention, above described, due to the act that two of the four strokes of the cycle, viz, the combustion and exhaust strokes, are power strokes and that the added power stroke is occasioned without placing any added lead cut to the power represented by the ther increases the effectiveness of the pri-.

mary work stroke of the engine, particularly if the valve timing is such that the admission valve opens just before the exhaust valve closes.

While I have shown my invention in, but two forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of variousother changes and modifications without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed there upon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is 1. A means for utilizing heat energy transmitted by the walls of an internal combustion engine having a cylinder with a fuel admission valve and an exhaust valve communicating with one end thereof, comprising water jackets for the walls of the eylinder, a steam separating chamber, means for producing a positive circulation of water through the water jackets and steam separating chamber for generating a continuous supply of steam, a chamber, means for delivering exhaust gases through the exhaust valves to the chamber, an ejector arranged to maintain a sub-atmospheric pressure in the chamber and the exhaust means, and a conduit for delivering a continuous supply of steam from the separating chamber to the ejector, whereby a sub-atmospheric pressure is maintained Within the'cylinder during the exhaust stroke of theengine for the purpose of producing a secondary power stroke upon the exhaust stroke of the engine.

2. In combination with an internal combustion engine of the four-cycle type, having a cylinder with a fuel inlet valve and a valve-controlled exhaust port in one end of the cylinder, a chamber, means to deliver the burned gases during the exhaust stroke of the engine from the exhaust port to the chamber, an ejector arranged to maintain a sub-atmospheric pressure in the chamber and the exhaust means, a water jacket for the cylinder. :1 steam-separating chamber, means for producing a positive circulation of water through the water jackets and steam-separating chamber for collecting thesteam gen erated in the cylinder jacket. and a conduit for delivering a continuous supply of steam from the separating chamber to the ejector, whereby a sub-atmospheric pressure is maintained within the cylinder during the exhaust stroke of the engine for the purpose of producing a secondary power stroke upon' the exhaust stroke of the engine.

In testimony whereof, I have hereunto subscribed my name this 28th day of December, 1920.

HERBERT T. HERB. 

